My recently purchased 2004 Nacra 570 has a Harken Ratchamatic 57C triple block on the main sheet (I believe it is a #2618). I've never had one before but from what I can tell the ratchet function does not seem to be engaging at all, even when sheeted in under heavy load. I checked the adjustment screw and it is currently set at 2 ¾ turns out from the bottom (2 ¾ turns counter clockwise). If I read the manual correctly I think I should move the screw out more to achieve engagement at lower force but I’m not sure how far out you can adjust the screw? I am not familiar with these blocks so I am looking for ideas on how to adjust or change the block so that it engages or maybe determine if there is a mechanical problem. I sent this message to Harken techical support but did not get a reply. I'd appreciate any personal experience or ideas you may have to offer.

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Steve - Texas Gulf Coast

91 Mystere 5.0 (sold)
04 Nacra 570 (sold)
08 Hobie Wave
00 Taipan 4.9
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#2630 is the ratchamatic. If you have the #2618, I'm pretty sure it is not a ratchamatic. See if you can move the center sheave by hand in an up and down motion, that is what engages/release the ratchet function. They will sometimes get frozen from salt deposit. It is easy to break free by hand. Soak it in fresh water. You can also add a mild detergent but I find that rarely necessary.

The adjustable screw is an allen screw accessible from the center sheave. We always screw them all the way out and back it off a 1/4 turn. Occasionally turn the screw back and forth just to keep it free.

The ratchet function engages easily even with the allen screw all the way out. I have seen them fail to engage, usually related to deposits. Harken is exceptional when it comes to customer service. Try Jim Bourne at Harken, he's the contact for small boat hardware.

Damon, please change the title of the thread to "Harken"





Edited by mummp on Jul 29, 2013 - 03:36 PM.

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Philip
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Oops. Just noticed the spelling error. Thanks for the input. It is a ratchamatic but the center sheave does not move. I will try the water soak suggestion to see if I can get it freed up. Thanks.

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Steve - Texas Gulf Coast

91 Mystere 5.0 (sold)
04 Nacra 570 (sold)
08 Hobie Wave
00 Taipan 4.9
--

When you say screw the allen screw all the way out, what are you meaning? I'm thinking clockwise (in), counterclockwise (out)? So you are saying 1/4 turn from that final position? Just trying to make sure I interpret this correctly.

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Steve - Texas Gulf Coast

91 Mystere 5.0 (sold)
04 Nacra 570 (sold)
08 Hobie Wave
00 Taipan 4.9
--

I had the same issue

Harken said to soak it in almost boiling water to break up the salts

Didn't fix it, so Harken had me send it in. They replaced the center block and sent it back (they did assemble it incorrectly, but i was able to fix that)

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I will try the water soak suggestion to see if I can get it freed up. Thanks.

Damon, thanks for correcting my typo! I soaked it in hot water last night and loosened the set screw and it moves but not easy/smooth in my inexperienced opinion. I will try to set up a system to test it this evening to see if the ratchet engages. Andrew, if I take it apart are pieces going to fly apart in my hand or is it fairly simple to disassemble and put back together?

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Steve - Texas Gulf Coast

91 Mystere 5.0 (sold)
04 Nacra 570 (sold)
08 Hobie Wave
00 Taipan 4.9
--

fun2themax

It is a ratchamatic but the center sheave does not move.

Steve, you're gonna have to put on some Def Leppard and bitch slap it! Try harder to move the center sheave UP towards the becket, that engages the ratchet. You can do it by hand or use a large screw driver for leverage if you are weak. Cycle the up and down movement several time. Soaking it for hours and/or days can't do anything but help.

If you didn't know the seller, there is always the slightest remote possibility that he pawned you a defective block.

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Philip
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Or... shackle it to something and use a line (with gloves) to pull upward while you pull the line back and forth

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You can do it by hand or use a large screw driver for leverage if you are weak.

Not sure if it will explode, but i am sure there are lots of bearings in it
It is not meant to be opened, you will have to drill out the rivet/pins, how are you going to re-secure it after that?

Harken will fix it (without receipt, or question) for FREE.. if you open it you may void that warranty

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Andrew, if I take it apart are pieces going to fly apart in my hand or is it fairly simple to disassemble and put back together?

If it is not meant to be taken apart then I will leave that to the professionals. I will try the " put on some Def Leppard and ***** slap it" technique though! The previous owner just sailed the boat from mast up storage for 5 years and best I can tell never did any maintenance so I spent the winter catching up on 5+ years of maintenance upgrades. I just found this issue and I doubt that he even new that it wasn't functioning right. I will find a place to put some tension on it and see if I can get it to work. Thanks for the help.

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Steve - Texas Gulf Coast

91 Mystere 5.0 (sold)
04 Nacra 570 (sold)
08 Hobie Wave
00 Taipan 4.9
--

to be honest, i didnt know for about a year myself, (and i never cleat from the wire), so it was a very nice "upgrade" when i finally had the unit working correctly

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I just found this issue and I doubt that he even new that it wasn't functioning right

Same here. I didn't really notice the first couple laid back outings in lighter air. But on the last outing riding on the edge in heavier air I ended up with some serious blisters and it became obvious that something was missing (besides my gloves)!

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Steve - Texas Gulf Coast

91 Mystere 5.0 (sold)
04 Nacra 570 (sold)
08 Hobie Wave
00 Taipan 4.9
--

I worked the sheave with a screw driver for a while to get it moving (had to run the Def Leppard track on repeat for a while). Got it moving better but still felt a little rough to me and really wasn't sure how it should be. So, I rigged the block to my fifth wheel hitch, put on my trap harness and used my weight to get enough force on it to test it. Bottom line is I did get the ratchet engaging and disengaging so I worked it on and off with this set up for a while (My neighbors probably think I flipped out). I'll try it under sail this Saturday and see how it does but I am optimistic at this point. Thanks for your tips and ideas.

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Steve - Texas Gulf Coast

91 Mystere 5.0 (sold)
04 Nacra 570 (sold)
08 Hobie Wave
00 Taipan 4.9
--

Great!
It could only help to soak it again in hot hot hot water (not boiling) to further free up salts now that you have gotten the unit to engaging

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Bottom line is I did get the ratchet engaging and disengaging

A late update. After a couple month hiatus from sailing I was finally able to get the cat out and confirm that the ratchamatic is engaging and disengaging properly now so i guess the above mentioned techniques worked. Thanks again for the input and ideas.

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Steve - Texas Gulf Coast

91 Mystere 5.0 (sold)
04 Nacra 570 (sold)
08 Hobie Wave
00 Taipan 4.9
--